There is an old thread on this. Try searching for bike and see if you can locate it. Members have done it. As you may know, the B gas version was sold in Canada so it may be that parts to attach your bike rack should be available. You might try searching via google for that.
Enjoy the ride.
Jeff in NYC
MB '06 E500W; MB '81 380SL
Retired: MB '17 B250e; MB '14 Be